102 research outputs found
Towards to personal profiles of online video game players: application of POS-PLS on UTAUT model
There are diverse segmentations of online players in the literature. Most of them are proposed a priori, and there are no segmentations based on the acceptance of technology and the personal values of the players. The foremost purpose of this study is to obtain a clustering of online video
games players, founded on UTAUT model, and to describe the subsequent segments consistent with the personal values of Schwartz. The measurement model and the structural model was analyzed with partial least squares (PLS). Subsequently, the POS-PLS technique has been devoted to inspect unobserved heterogeneity and to find players’ segments. Four segments are
obtained from the statistical tools
A U-Pb Study of Zircons from a Lower Crustal Granulite Xenolith of the Spanish Central System: A Record of Iberian Lithospheric Evolution from the Neoproterozoic to the Triassic
A U-Pb laser ablation inductively coupled plasma mass spectrometry and secondary ion mass spectrometry geochronological study has been performed on zircons from a felsic granulite xenolith from the lower crust under the Variscan belt of Iberia. The ages obtained reveal zircon-forming events that span from the late Neoproterozoic (Cadomian-Avalonian orogeny) to the early stages of the opening of the Atlantic Ocean in the Mesozoic, through Cambro-Ordovician rifting, Devono-Carboniferous Variscan-Alleghenian collision, and Permian-Triassic extension and uplift. The U-Pb age groups found in zircons from this single lower crustal xenolith (ca. 220, 250, 280–310, 460–490, 525, and 550–490 Ma) record at least one complete cycle of closing and opening of oceanic basins and collision of continental masses. Zircons from the felsic granulite xenolith contain a synthesis of the geochronological information found on the surface geology and record most but not all major lithospheric events in the region in a ca. 400-m.yr. period
Cultura Trabajo-Familia y Engagement en trabajadores de un CESFAM del sector rural de la región del Maule
76 p.Esta investigación tiene como objetivo analizar la relación entre las variables de
Cultura Trabajo-Familia y el Engagement presente en los trabajadores del Centro de Salud Familiar de un sector rural de la región del Maule. El estudio posee un alcance descriptivo correlacional de carácter transversal, se aplicó a una muestra total de 76 personas; asimismo, no existió una manipulación de los investigadores sobre las variables en
cuestión, es decir, es un estudio no experimental. Para la recolección de la información se entregó un dossier que contenía una carta de presentación de parte del subdirector del CESFAM, el consentimiento informado para los encuestados, el instrumento de Cultura
Trabajo-Familia y la Utrecht de Engagement en el Trabajo (UWES). En lo que respecta a
los resultados obtenidos, se encontró que en la institución existe una “Moderada Cultura
Trabajo-Familia” y un “Alto Nivel de Engagement”. Por su parte al correlacionar las dos variables mencionadas con anterioridad se obtuvo que existe una asociación negativa y significativa. Al finalizar, se contrarrestaran lo obtenido con la literatura revisada considerando las implicancias y limitantes del estudio, además de la apertura de nuevas
investigaciones aplicadas al área de salud.
Palabras claves: Cultura Trabajo-Familia, Engagement, Políticas de Conciliación Trabajo- Familia
A pre-Rodinian ophiolite involved in the Variscan suture of Galicia (Cabo Ortegal Complex, NW Spain)
U–Pb dating of zircons from a metagabbro of the Purrido
amphibolitic unit (Cabo Ortegal Complex, NW Iberian
Massif) yielded an age of 1159 ± 39 Ma, interpreted to
approximate the crystallization age of the gabbroic protolith.
Considering the arc affinity of the metagabbroic rocks, the
unit is interpreted as a pre-Rodinian ophiolite developed in a
back-arc setting. It is suggested that the ophiolite was
obducted over the West African terranes during the assembly
of Rodinia. There, this terrane remained tectonically stable
and facing an ocean for a long time, and eventually became
part of the Gondwanan margin. The ophiolite was finally
involved in the Variscan suture of Galicia where it is
sandwiched between Palaeozoic rocks. The Purrido unit is so
far the only example of a Mesoproterozoic ophiolite in the
European Variscan belt, where pre-Neoproterozoic rocks are
very scarce and restricted to small exposures
Supporting info item, In: "Using SHRIMP zircon dating to unravel tectonothermal events in arc environments. The early Palaeozoic arc of NW Iberia revisited"
Dating of zircon cores and rims from granulites developed in a
shear zone provides insights into the complex relationship
between magmatism and metamorphism in the deep roots of
arc environments. The granulites belong to the uppermost
allochthonous terrane of the NW Iberian Massif, which forms
part of a Cambro-Ordovician magmatic arc developed in the
peri-Gondwanan realm. The obtained zircon ages confirm that
voluminous calc-alkaline magmatism peaked around 500 Ma
and was shortly followed by granulite facies metamorphism
accompanied by deformation at c. 480 Ma, giving a time
framework for crustal heating, regional metamorphism, deformation
and partial melting, the main processes that control the
tectonothermal evolution of arc systems. Traces of this arc can
be discontinuously followed in different massifs throughout the
European Variscan Belt, and we propose that the uppermost
allochthonous units of the NW Iberian Massif, together with the
related terranes in Europe, constitute an independent and
coherent terrane that drifted away from northern Gondwana
prior to the Variscan collisional orogenesis
Two-stage collision: Exploring the birth of Pangea in the Variscan terranes.
The Variscan suture exposed in NW Iberia contains a stack of terranes including two allochthonous units with continental affinity and Gondwanan provenance (Upper and Basal Units), separated by an ophiolite belt where the most common units show protolith ages at c. 395 Ma. Recent Lu–Hf zircon data obtained from these ophiolites indicate interaction between the gabbroic magmas and old continental crust. Hence, the ophiolites could not have originated in a deep ocean basin associated with a mature mid-ocean-ridge or intraoceanic subduction. The tectonothermal evolution of the continental terranes bounding the suture zone records two consecutive events of deep subduction. The Upper Units record an initial high-P/ultra-high-P metamorphic event that occurred before 400–390 Ma, while the Basal Units were affected by a second high-P/low-to-intermediate-T metamorphic event dated at c. 370 Ma. Continental subduction affected the most external margin of Gondwana and developed in a setting of dextral convergencewith Laurussia. Development of the two high-P events alternated with the opening of an ephemeral oceanic basin, probably of pull-apart type, in Early Devonian times. This ephemeral oceanic domain is suggested as the setting for the protoliths of the most common ophiolites involved in the Variscan suture. Current ideas for the assembly of Pangea advocate a single collisional event between Gondwana and Laurussia in the Carboniferous. However, the new evidence from the allochthonous terranes of the Variscan belt suggests a more complex scenario for the assembly of the supercontinent, with an interaction between the colliding continental margins that started earlier and lasted longer than previously considered. Based onmodern analogs of continental interaction, the development of complex collisions, as here suggested for Gondwana and Laurussia during the assembly of Pangea, could have been the norm rather than the exception throughout Earth history
Magmatism and early-Variscan continental subduction in the northern Gondwana margin recorded in zircons from the basal units of Galicia, NW Spain
In situ uranium-lead dating (LA-SF-ICPMS
and SIMS) and Lu-Hf isotope analyses
(LA-MC-ICP-MS) of zircon from eclogite
facies rocks from the basal units of the
Variscan Belt in Galicia constrain their magmatic
and metamorphic evolution and give
some clues about the nature and origin of
the involved basement. The samples studied
are two felsic gneisses, two eclogites, and one
eclogitic gneiss of intermediate composition
(metatonalite). Oscillatory-zoned zircon cores
from the felsic samples gave a main clustering
of U-Pb ages at 493 ± 2 and 494 ± 2 Ma, and
some older ages that represent inherited cores.
Zircon grains from the intermediate and one
of the mafi c rocks show no inherited cores
and yielded ages of 494 ± 3 and 498 ± 6 Ma,
respectively, interpreted as time of protolith
crystallization. Variably developed homogeneous
zircon rims in one felsic gneiss
yielded an age of 372 ± 3 Ma, and very tiny
zircons of one eclogite gave 350 ± 2 Ma, both
of which we interpret as metamorphic ages.
The new age data demonstrate that the
calc-alkaline magmatic suite described in
the basal unit is ca. 20 Ma older than the alkaline
to peralkaline plutonic suite of the same
unit (dated at 472 ± 2 Ma; Rodríguez et al.,
2007), and thus probably represents a distinct
geologic event. Overgrowth rims are interpreted
as metamorphic on the basis of their
Lu/Hf and Th/U ratios. The 372 ± 3 age is
considered as dating the high-pressure (high-P)
metamorphism, and is essentially in agreement
with previous Ar-Ar and Rb-Sr data.
This high-P metamorphism marks the initial
early-Variscan subduction of the Gondwana
margin. The inherited zircon ages and Hf isotopic
composition of zircons point to a considerable
input of crustal material with West African
Craton provenance to the felsic magma
Seasonal temperatures from δ18O in Recent Spanish tufa stromatolites: Equilibrium redux!
This study focuses on recent debate over the value of stable-isotope-based environmental proxies recorded in riverine tufa-stromatolites. We recovered a 12-year record (1999-2012) of river-bed tufa stromatolites in the River Piedra (NE Spain) along with a partly overlapping 15-year record (1994 to 2009) of accumulations in a drainage pipe: both deposits formed in water with near identical physico/chemical parameters. Measured water temperature (Tw) data and near constant δ18Owater composition allowed selection of an ‘equilibrium’ palaeotemperature equation that best replicated actual temperatures. We found, as other have, that both the Epstein et al. (1951) and Kim & O’Neil (1997) formulas for Tw calculation from equilibrium calcite δ18O compositions were appropriate for the River Piedra where tufa deposition rates are high, means between 5.6 and 10.8 mm in six months. δ18Ocalcite in both the river and the pipe deposits record essentially the full actual seasonal Tw range. Only the coldest times (Tw < 10ºC), when calcite precipitation mass decreased to minimum, are likely to be unrepresented, an effect most noticeable in the pipe where depositional masses are smaller and below sample resolution. While we cannot rule out kinetic effects on δ18Ocalcite-based calculated Tw, the good fit between measured Tw and δ18Ocalcite-calculated Tw indicates that temperature is the principal control. Textural and deposition rate variability between the river and pipe settings are caused by differences in flow velocity and illumination. In the river, calcification of growing cyanobacterial mat occurred throughout the year, producing composite dense and porous laminae, whereas in the pipe, discontinuous cyanobacterial growth in winter promoted more abiogenic calcification. High-resolution δ18Ocalcite data from synchronous pipe and river laminae show that reversals in Tw occur within laminae, not at lamina boundaries, a pattern consistent with progressive increase in calcite precipitation rate as cyanobacterial growth re-established in spring
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